JP2002100922A - Helical antenna and method for attaching antenna coil to substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a helical antenna, that can be reduced in size at a low cost, and to provide a method for attaching the antenna to a substrate. SOLUTION: The helical antenna 11 is constituted with a helical coil 12 having an inside diameter, which is almost equal to the width of an antenna guide section 3 formed in the main body of a printed board 1, being slid on the guide section 3. The lower end section of the coil 12 is inserted into a through-hole 15 of a feeding land 13, provided in the lower part of the guide section 3, and the upper end section of the coil 12 is inserted into the through- hole 15 of an adjustable pattern 14 provided in the upper part of the guide section 15. Both end sections of the coil 12 are fixed by soldering, after their positions have been confirmed. The frequency characteristic of the helical antenna 11 is adjusted by appropriately cutting the adjustable pattern 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a helical antenna and a method for mounting an antenna coil on a substrate.

[0002]

2. Description of the Related Art With the spread of portable communication devices, there has been a demand for smaller and thinner housings without protrusions and housings in order to improve portability. In order to eliminate the projection of the housing, it is necessary to house the antenna inside the housing. When the antenna is built in the housing, there is a problem that the resonance frequency of the antenna varies due to the variation in the relative positional relationship between the antenna and the printed (circuit) substrate. Therefore, there is a need for a printed circuit board on which an antenna having a small variation in resonance frequency is mounted, and a method for mounting the same.

[0003] In addition, there is a demand for a smaller and thinner antenna itself housed in a portable communication device. For this reason, a so-called helical antenna, which is formed by forming a linear metal material in a helical shape and increasing the linear density of the electric capacitance of the antenna to enable miniaturization, is widely used.

FIGS. 8A to 8D show an example of a helical antenna mounted on a printed circuit board based on the prior art. FIGS. 8A and 8B show an example in which the leading end 32 a of the helical coil 32 on the power supply point side is fixed to the fixing plate 34 of the printed circuit board 21 by soldering. FIG. 8 (c), (d)
Shows an example in which the helical coil 32 wound around the spacer 35 is attached to the printed circuit board 21. The distal end 32a of the helical coil 32 is soldered to a joint 37 that joins the fixed frame 36 fitted to the spacer 35 and the printed circuit board 21.

[0005] For example, Japanese Patent Application Laid-Open No. 9-36644 discloses a technique related to the antenna shown in FIGS. 8 (c) and 8 (d). According to this technique, as shown in FIG. 9, the mounting portion 43 is inserted into the antenna coil 42, and both ends thereof are fitted to a pair of base portions 44 fixed to the wiring board 50,
One end 42a of the antenna coil is fixed to the wiring board 50 by soldering.

[0006]

In the helical antenna 31 shown in FIGS. 8A and 8B, it is difficult to make the mounting angle and the position of the helical antenna 31 constant with respect to the printed circuit board 21. Etc. cannot be made constant. On the other hand, the helical antenna 31 shown in FIGS.
The use of No. 6 has the disadvantage that the manufacturing cost is increased, and the miniaturization and thinning of the antenna are also restricted.

The present invention has been made in view of the above situation, and has as its object to provide a helical antenna and a method of attaching an antenna coil to a substrate at low cost and having stable antenna performance. It is another object of the present invention to provide a method for attaching a helical antenna and an antenna coil to a substrate, which can be easily reduced in size and thickness.

[0008]

In order to achieve the above object, a helical antenna according to a first aspect of the present invention comprises a substrate, an antenna guide forming a part of the substrate, and a coil wound around the antenna guide. And a turned antenna coil.

According to this structure, the antenna coil is wound around the antenna guide part forming a part of the substrate,
A helical antenna integrated with the substrate is obtained. Since a mounting member such as a spacer is not used, a helical antenna having stable antenna performance at low cost can be obtained. In addition, it is easy to reduce the size and thickness of the substrate and the housing that accommodates the substrate.

[0010] The substrate may be provided with a slit, and the antenna coil may be wound around an antenna guide portion which is a part of the substrate defined by the slit. In this case, the substrate is provided with the antenna guide part as a part thereof, and the antenna coil wound around the antenna guide part can secure a fixed position with respect to the substrate, thereby exhibiting highly reliable antenna performance. You. Further, since the substrate has no projection, the size of the housing can be easily reduced.

[0011] The substrate may have a protruding portion, and an antenna coil may be wound around an antenna guide formed by the protruding portion. In this case, the substrate includes the antenna guide portion as a part thereof, and similarly, the antenna coil can secure a fixed position with respect to the substrate, thereby exhibiting highly reliable antenna performance.

One end of the antenna coil may be connected to a feeding point provided on the substrate, and the other end of the antenna coil may be connected to a pattern for adjusting the resonance frequency of the antenna formed on the substrate. One end of the antenna coil may be connected to a feeding point provided on the substrate, and the other end of the antenna coil may be connected to a capacitor crown mounted on the substrate. Since the capacitor crown can have a large capacitance, it is possible to further reduce the size of the antenna.

[0013] The antenna guide may have notches (recesses) at both ends, and the antenna coil may be wound around the notches. Through holes are formed at both ends of the antenna guide portion, and both ends of the antenna coil are provided with bent portions bent at the center of the coil. Both ends of the antenna coil are inserted into the through holes, and the bent portions contact the substrate. You may push it up. Thus, the position of the antenna coil with respect to the substrate can be determined. The antenna coil may have a circular and / or polygonal shape.

In order to achieve the above object, a method for mounting an antenna coil on a substrate according to a second aspect of the present invention is as follows.
A method of attaching an antenna coil to a substrate, the method comprising: forming through holes at both ends of an antenna guide part forming a part of the substrate; bending both ends of the antenna coil; and attaching the antenna guide part to the antenna coil. It is characterized by comprising a step of inserting, a step of inserting both ends of the antenna coil into the through holes, and a step of soldering and fixing both ends of the antenna coil to the substrate.

According to this method, both ends of the antenna coil are inserted into the through holes provided in the antenna guide, and the mounting position is determined. Later, stable antenna performance can be exhibited.

An antenna coil inserted into the antenna guide may be wound around notches formed at both ends of the antenna guide forming a part of the substrate. The wound antenna coil may have a circular and / or polygonal shape. Since the antenna coil is fixed by the notch, displacement and deformation of the antenna coil can be suppressed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for mounting a helical antenna and an antenna coil on a substrate according to an embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 shows a configuration of a printed circuit board 1 including a helical antenna according to the embodiment. FIG. 1A shows a helical antenna 11.
FIG. 1 is a front view of a printed circuit board 1 on which
(B) is a side view thereof. As shown in FIGS. 1A and 1B, the helical antenna 11 has an antenna guide 3 surrounded by a slit provided on the printed board 1 and an end of the printed board 1, and one end of the antenna guide 3. The provided resonance frequency adjustment pattern (hereinafter referred to as an adjustment pattern) 14 and the power supply land (hereinafter referred to as a power supply land) 13 provided at the other end of the antenna guide portion 3.
And a helical coil 12 which is an antenna body.

The slit 2 has no restriction on the shape, such as the precision, width, curvature, or the like of the machined surface as long as it does not hinder the work when the helical coil 12 is externally fitted to the antenna guide portion 3.

The antenna guide section 3 includes a helical coil 1
It has almost the same width as the inside diameter of the second. Antenna guide part 3
Is dependent on the pitch, number of turns, and length of the helical coil 12 to be fitted, and is designed to obtain desired antenna performance.

The power supply land 13 has a function of supplying power to one end of the helical coil 12 to be connected, and
2 has a function of fixing one end.

The adjustment pattern 14 corresponds to the helical coil 12
The other end of the helical coil 12 is connected, and the capacitance is adjusted by, for example, changing the area or the like, so that the coupling capacitance between the helical coil 12 and the adjustment pattern 14 is adjusted to obtain a desired resonance frequency. Have. Further, it also has a function of fixing the other end of the helical coil 12 by soldering.

The helical coil 12 is formed of a wire made of metal or another conductor, and is formed in a spiral shape having an inner diameter substantially equal to the width of the antenna guide 3. The pitch, number of turns, length, helical diameter, etc. of the helical coil 12 affect the frequency characteristics of the antenna, and these factors are designed to obtain desired antenna performance.

The helical coil 1 is mounted on the antenna guide 3.
2 is externally fitted. Since the inner diameter of the helical coil 12 and the width of the antenna guide portion 3 are substantially the same, a displacement or the like of the helical coil 12 after the outer fitting is suppressed.

Both ends of the helical coil 12 externally fitted to the antenna guide portion 3 are inserted into through holes 15 penetrating the printed circuit board 1 formed on the power supply lands 13 and the adjustment pattern 14 (FIG. 1 ( b)). After the positions of both ends of the helical coil 12 are once fixed, one end is fixed to the power supply land 13 by soldering, and the other end is fixed to the adjustment pattern 14 by soldering. The helical coil 12 is fixed in a state in which the positions of both ends are fixed, and since the inner diameter of the helical coil 12 and the width of the antenna guide portion 3 are substantially the same, the displacement of the helical coil 12 and its deformation are suppressed. Therefore, the helical antenna 1
No. 1 can exhibit highly reliable antenna performance.

Next, a method of attaching the helical coil 12 to the printed circuit board 1 will be described.

FIG. 2 shows an external view of the helical coil 12. FIG. 2A is a perspective view of the helical coil 12, and FIG.
FIG. 2B is a top view of the helical coil 12.

One end of the helical coil 12 is first bent from the coil circumference toward the center to form a bent portion 12c. Next, in order to easily penetrate the coil tip 12a into the through hole 15 formed at one end of the antenna guide 3, the coil is bent from the coil center toward the coil circumference to form a bent portion 12b.

On the other hand, the other end of the helical coil 12 is first bent from the coil circumference toward the center, and
g, and further bent downward at the center,
The bent portion 12f is formed. Next, the antenna guide 3
The coil tip 12 is inserted into a through hole 15 formed at the other end of the coil.
In order to make d easy to penetrate, it is bent from the coil center toward the coil circumference to form a bent portion 12e.

FIG. 3 is a front view showing the details of the antenna guide 3 to which the helical coil 12 is attached, which is a part of the printed circuit board 1 shown in FIG.

A plurality of semicircular notches 5 are provided at both ends of the antenna guide 3 at a predetermined pitch.
The semicircular cutout 5 is provided with the helical coil 1 fitted outside.
2 has a function of fixing and suppressing a deviation. Next, FIG.
The helical coil 12 having the shape shown in FIG. 1 is mounted on the antenna guide 3 having the cutouts 5 at both ends.

First, the helical coil 12 is externally fitted along both side ends of the antenna guide 3. Helical coil 1
2 is inserted into the through hole 15 and fixed to the power supply land 13 by soldering. Next, while applying an appropriate tension to the helical coil 12, the antenna guide 3
According to the semicircular notch 5 provided at both ends of the
The helical coil 12 is wound from the lower coil. Finally, the upper end 12a of the helical coil 12 is inserted into the through hole 15, and is fixed to the adjustment pattern 14 by soldering.

The resonance frequency of the helical antenna 11 is realized by cutting the adjustment pattern 14 for adjusting the resonance frequency and appropriately adjusting the area (electric capacity).

According to the mounting method described above, the helical coil 12 is fixed to the semicircular cutouts 5 provided at both ends of the antenna guide 3. Helical coil 12
The ends of the helical coil 12 are fixed by soldering after they are inserted into the through holes 15 and the mounting position is determined, so that variations between lots during mounting and displacement and deformation of the helical coil 12 after mounting are suppressed. It is possible.

In the above embodiment, first, the lower end 12d of the helical coil 12 is soldered to the power supply land 1.
3, the helical coil 12 is fixed to the cutouts 5 on both side ends of the antenna guide 3, and finally, the upper end 12 a of the helical coil 12 is fixed to the adjustment pattern 14 by soldering. However, helical coil 1
The lower end portion 12d and the upper end portion 12a may be fixed at the same time.

In the description of the above embodiment, the lower end 12d and the upper end 12a of the helical coil 12 are inserted into the through hole 15 to determine the mounting position.
Instead of the through hole 15, for example, a positioning hook or the like can be used.

In the above embodiment, the helical coil 12
It has been described that the upper end portion 12a is soldered after being inserted into the through hole 15 provided in the adjustment pattern 14,
It may be an open end whose position has been determined without being soldered.

In the above embodiment, the antenna guide 3
It has been described that the cutouts 5 formed at both end portions of the helical coil are semicircular. However, if the concave portion has a function of suppressing the displacement of the helical coil 12 to be fitted, the shape thereof is semicircular. It is not limited to this and is arbitrary.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
An embodiment will be described. FIG. 4A is a front view of the printed circuit board 1 on which the helical antenna 11 is mounted, and FIG.
(B) is a side view thereof. Helical antenna 11
The antenna guide 3 defined by the slit 2 and the end of the printed circuit board, the adjustment pattern 14 provided on the upper part of the antenna guide 3, and the antenna guide 3
And a helical coil 12 which is an antenna body.

As shown in FIG. 4A, the configuration of the helical antenna 11 except that the antenna guide 3 is defined by two slits 2 and the end of the printed circuit board 1 is shown in FIG. ) And the helical antenna 11 shown in FIG. Therefore, the components are denoted by the same reference numerals.

The method of attaching the helical coil 12 to the printed circuit board 1 is the same as the method described in the first embodiment.

In this embodiment, the helical coil 12
Is not directly exposed to the side edge of the printed circuit board 1, so that when the printed circuit board 1 is mounted on a portable communication device or the like, the helical coil 12 does not cause displacement or deformation due to direct contact with the housing. Therefore, it is possible to maintain stable antenna performance after mounting the printed circuit board 1.

As described in the first and second embodiments, the helical coil 12 is externally fitted to the antenna guide 3 formed on the printed circuit board 1, and
2 at one end to the power supply land 13 and the other end at the adjustment pattern 1
After being inserted into the through hole 15 provided in 4 and determining the position, both ends are fixed by soldering. Simply put,
The helical antenna 11 is mounted on the printed circuit board 1 without using any special antenna mounting parts such as a spacer. Therefore, it is possible to obtain the helical antenna 11 that is easy to reduce in size and thickness at low cost and has little variation in antenna performance due to variation and deformation of the antenna position after mounting.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
2 shows a helical antenna according to the embodiment. FIG. 5 (a)
FIG. 5B is a front view of the printed circuit board 1 to which the helical antenna 11 is attached, and FIG. 5B is a right side view thereof. As shown in FIG. 5A, the helical antenna 11
Are an antenna guide portion 4 formed from a projecting portion provided on the printed circuit board 1, an adjustment pattern 14 provided at one end of the antenna guide portion 4, and a power supply provided at the other end of the antenna guide portion 4. It comprises a land 13 and a helical coil 12 which is an antenna body.

The configuration of the helical antenna 11 is the same as that of the first embodiment except that the antenna guide portion 4 is formed from a projecting portion provided on the printed circuit board 1, and the same components are the same. Is assigned.

The antenna guide 4 formed of the projection has a width substantially equal to the inner diameter of the helical coil 12. The length of the antenna guide 4 depends on the pitch, the number of turns, and the length of the helical coil 12 to be fitted, and is designed to obtain desired antenna performance.

Helical coil 1 according to this embodiment
In the method of attaching 2 to the printed circuit board 1, a helical coil 12 shown in FIG. 2 is used. As shown in FIG. 6, an antenna guide 4 having the same configuration as that of the antenna guide 3 shown in FIG. Will be implemented.

In the third embodiment, the helical antenna 11 is a circuit element (not shown) on the printed circuit board 1.
Therefore, the electromagnetic effect of the circuit element on the helical antenna 11 is minimized. Therefore, it is possible to maintain stable antenna performance and improve sensitivity.

FIGS. 7A and 7B show a modification of the first embodiment and a modification of the third embodiment, respectively.

As shown in FIGS. 7A and 7B, the antenna guides 3 and 4 are different from the antenna guides 3 and 4 except that a capacitor crown 16 is provided at one end of the antenna guides 3 and 4. Is similar to those of the first and third embodiments. Therefore, the same reference numerals are given to the same components, and the same description will be omitted.

The capacitance crown 16 is fitted as a separate member to the ends of the antenna guides 3 and 4, and one end of the helical coil 12 is connected. Helical coil 1 connected in series
The coupling capacitance between 2 and the capacitance crown 16 (ie, the sum of the respective capacitances) is
Since a constant value is required to obtain a desired resonance frequency, the capacitance of the antenna coil 12 can be small because the capacitance crown 16 has a large capacitance. Therefore, the use of the capacitor crown 16 allows the helical antenna 11 to be downsized. Further, the capacity crown 16
Through hole 1 having one end of helical coil 12 at the end
5, and has a function of fixing the position by soldering after fixing the position.

In the above-described modification, the cap 16 has been described as being separately fitted to the ends of the antenna guides 3 and 4 as a separate member. May be implemented.

The present invention is not limited to the description of the above embodiment, and various applications and modifications are possible. For example,
The material, the number of turns, the spiral diameter, the thickness, the cross-sectional shape, the pitch, and the like of the helical coil 12 are selected or designed to obtain the desired frequency performance of the antenna, and are not particularly limited. Although the antenna guides 3 and 4 are formed at the end of the printed circuit board 1, there is no restriction on the relative position in the printed circuit board 1, and the position is arbitrary. Furthermore, although the outer shape of the helical coil 12 has been described as being circular, it may be, for example, a polygon.

In the above description of the embodiment, the helical antenna 11 is attached to the printed circuit board 1. However, for example, a circuit board, another wiring board, or an electronic circuit patterned by a method other than printing is provided. It may be a substrate.

[0055]

According to the present invention, it is possible to provide a helical antenna and a method for attaching an antenna coil to a substrate, which are stable at low cost, have stable antenna performance, and can be easily miniaturized.

[Brief description of the drawings]

FIG. 1 is an example of a printed circuit board to which a helical antenna according to a first embodiment of the present invention is attached.

FIG. 2 is a detailed view showing an example of a helical coil according to the embodiment of the present invention.

FIG. 3 is a diagram showing details of an antenna guide unit to which the helical coil according to the first embodiment of the present invention is attached.

FIG. 4 is an example of a printed circuit board to which a helical antenna according to a second embodiment of the present invention is attached.

FIG. 5 is an example of a printed circuit board to which a helical antenna according to a third embodiment of the present invention is attached.

FIG. 6 is a diagram illustrating an example of a method of attaching a helical coil according to a third embodiment of the present invention.

FIG. 7 is an example of a helical antenna according to a modification of the first and third embodiments of the present invention.

FIG. 8 is an example of a conventional method for mounting a helical antenna.

FIG. 9 is an example of a conventional helical antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 Slit 3 Antenna guide part 4 Projection part (antenna guide part) 5 Semicircular notch part 11 Helical antenna 12 Helical coil 13 Power supply land 14 Adjustment pattern 15 Through-hole 16 Capacity cap

Claims (11)

[Claims] 1. A helical antenna comprising: a substrate; an antenna guide forming a part of the substrate; and an antenna coil wound around the antenna guide. 2. The helical antenna according to claim 1, wherein the substrate has a slit, and the antenna guide portion is formed from a region defined by the slit of the substrate. 3. The helical antenna according to claim 1, wherein the substrate has a projecting portion, and the antenna guiding portion is formed by the projecting portion. 4. The substrate includes a feeding point for feeding the antenna coil, and a pattern for adjusting a resonance frequency of the antenna coil, and one end of the antenna coil is connected to the feeding point. The helical antenna according to claim 1, 2 or 3, wherein the other end of the antenna coil is connected to the pattern. 5. The substrate includes a feeding point for feeding power to the antenna coil, and a capacitor crown formed for adjusting a capacitance of the antenna coil. The helical antenna according to claim 1, wherein the helical antenna is connected to a feeding point, and the other end of the antenna coil is connected to the capacitor crown. 6. A notch portion is provided at both end portions of the antenna guide portion forming a part of the substrate, and the antenna coil is wound around the notch portion. 6. The helical antenna according to any one of items 5 to 5. 7. The antenna guide portion has through holes at both ends, both ends of the antenna coil have bent portions bent at the center of the coil, and both ends of the antenna coil are inserted into the through holes. The helical antenna according to any one of claims 1 to 5, wherein a bent portion is in contact with the antenna guide portion, and both ends of the antenna coil are fixed to the substrate. 8. The helical antenna according to claim 1, wherein the antenna coil has a circular and / or polygonal shape. 9. A method for attaching an antenna coil to a substrate, the method comprising: forming through holes at both ends of an antenna guide part forming a part of the substrate; bending both ends of the antenna coil; Inserting both ends of the antenna coil into the through-hole, soldering both ends of the antenna coil to the substrate, and fixing the antenna coil,
A method for attaching an antenna coil to a substrate, comprising: 10. A step of forming notches at both ends of the antenna guide, and a step of winding the antenna coil loosely fitted along both ends of the antenna guide around the notches. 10. The method according to claim 9, further comprising: attaching the antenna coil to a substrate. 11. The method for mounting an antenna coil on a substrate according to claim 9, wherein the antenna coil has a circular and / or polygonal shape.